PLAINFIELD — A high-ranking member of the Latin Kings street gang was sentenced today to 50 years in state prison, authorities said.

Francisco Demoscoso, 36, of Plainfield, was found guilty in September of first-degree attempted murder, second-degree aggravated assault and weapons offenses, and had been facing a possible life term, the Union County Prosecutor’s Office said.

Demoscoso and fellow gang member Jorge Acosta attacked a Plainfield man outside the Chez Marie nightclub in the early morning hours of Jan. 26, 2008, said Assistant Prosecutor Joshua McMahon, who prosecuted the case.

Demoscoso, who lists an aggravated assault among his eight previous convictions, appeared this morning before state Superior Court Judge Joseph P. Perfilio. The judge, sitting in Elizabeth, said the public needed to be protected from Demoscoso, calling him a “danger to society.”

A jury convicted the two in September after four hours of deliberation.

The stabbing after the victim had an altercation with his assailants, McMahon said. When the victim, who was not identified, ran from the club, Demoscoso and Acosta chased him down, McMahon said.

While Acosta attacked him, Demoscoso repeatedly stabbed him, the assistant prosecutor said. He said they left the man in the street for dead, but a good Samaritan flagged down a passing police car as the victim pleaded, “Don’t let me die.”

The victim was airlifted to a local hospital and survived the attack after extensive surgery, McMahon said.